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An Easy Dual-Band VHF/UHF vertical Antenna made with a TV twin lead and coax cable

Constructing a 2-meter 5/4 wave antenna, N1HFX details a design fully enclosed within 3/4-inch PVC tubing, addressing the significant velocity factor of PVC which necessitates a 19% reduction in physical length. The design incorporates a specific matching system using 300-ohm TV twin lead to counteract the highly inductive impedance component inherent in a 5/4 wave radiator. Key components include #18 stranded insulated wire for the radiating element, RG58/U coax, a PL259 connector, and a hardwood dowel for internal support, all carefully dimensioned for optimal performance within the PVC housing. The article provides precise cutting lengths for the twin lead and #18 wire, with the overall assembly measuring 77 3/4 inches, reflecting an approximate velocity factor of 0.81. Tuning instructions emphasize taking SWR readings with the antenna assembly inside the PVC, adjusting the #18 wire and twin lead in small increments to achieve a low SWR across the 2-meter band. The prototype antenna achieved SWR readings below 1.2:1 across the entire band, and N1HFX suggests an estimated 6 dB gain when properly mounted, offering a cost-effective alternative to commercial antennas.

The page describes two types of 2 meter J-Pole antennas, one made of copper pipe and a roll-up J-pole made of TV twin lead, providing dimensions, components, and construction details. It is authored by Dr. Carl O. Jelinek N6VNG.

J-pole Design Program V1.1 by WA2ISE Download a VHF twinlead Jpole antenna calculator MSDOS program

The G3TPW CobWebb antenna design provides a compact, horizontally polarized, omni-directional solution for 20m, 17m, 15m, 12m, and 10m bands. This antenna utilizes five full-size half-wave dipoles, each bent into a square configuration to achieve omni-directional radiation without the nulls typically found in straight dipoles. The design incorporates a single 50-ohm coaxial feedline with an integrated air-core choke balun, minimizing feeder radiation and reducing EMC issues. Construction details include using PVC-covered multi-stranded copper twin cable for elements, supported by a fiberglass cross. The document specifies tapping points for impedance matching to 50 ohms on all five bands, ensuring high radiation efficiency without lossy traps or loading coils. Physical dimensions are compact, with 2.6-meter (8.5 feet) sides and a total weight of 6 kg (14 lbs), making it suitable for mounting on a 20-foot aluminum scaffold pole. Detailed instructions for assembling the junction box, including terminal strip wiring and the coaxial choke balun, are provided with photographs and diagrams. The design emphasizes a confined electric field to reduce coupling to nearby conductors, which helps mitigate TVI and makes the antenna less sensitive to mounting height or ground conductivity.

The 20-meter homebrew **Moxon antenna** project by 9Y4DD, Dave, details the construction of a 14 MHz directional antenna using readily available and repurposed materials. Initial SWR readings at 6 feet were 1.2 at 14.000 MHz, 1.4 at 14.350 MHz, and 1.1 at 14.175 MHz, with a subsequent increase of 0.1 on all frequencies when raised to 15 feet. The design adheres to specifications provided by L.B. Cebik (W4RNL). Key components include a discarded domestic water pump pressure tank as the center mounting bracket, 1/2-inch PVC conduit for spreaders, and 1/2-inch CPVC hot water pipe inserts to enhance rigidity. The total weight of the antenna is 12.625 pounds, with a material cost of U.S.$36.63. The spreaders are 165 inches from the center, utilizing 2.5mm sq. stranded copper wire for the elements. Dave's design incorporates hexagonal 'spider webs' of waxed twine to stabilize the flexible PVC spreaders, addressing initial issues with wind-induced movement. Separators cut from 3/16-inch Plexiglas maintain an 8.6-inch element spacing. The antenna demonstrated effective DX contacts with Europe from Trinidad, showing improved noise reduction compared to an inverted V.

Demonstrates the construction and on-air performance of the _NB6Zep_ antenna, a modified 20-meter Extended Double Zepp design optimized for multi-band operation from 40 through 10 meters. The resource covers basic design principles, including dimensions of 66 feet horizontal and 5 feet vertical elements, and specifies open ladder line or TV twin lead for the transmission line. It details material selection for low-cost wire antenna construction, such as 18 AWG wire for the legs and ceramic or plastic insulators, along with practical tips for soldering connections and insulating against moisture. The author, NB6Z, shares insights from extensive _EZNEC_ modeling to optimize the antenna's total length for a 40-meter half-wave dipole footprint and feed line length for direct tuner connection. The article presents field results, including successful _PSK31_ contacts from Oregon to the East Coast on 40 and 30 meters with 50 watts, even at a low height of 6 feet. It provides detailed performance characteristics for each band, noting the _NB6Zep_'s highest gain (over 3 dB) and sharp, medium-angle lobes on 20 meters, which yielded strong DX reports to locations like Korea, Japan, and Argentina. For 17 and 15 meters, it describes a butterfly-like pattern with broad lobes, while 12 and 10 meters exhibit narrow, directional lobes in an "X" configuration. The author also shares personal experiences operating successfully for over a decade in an antenna-restricted environment using the NB6Zep and other stealth wire antennas.

The N2CKH travel special 300 Ohm ladder line convertable antenna

This Multiband Cubical Quad antenna a boomless Quad design with glass-fibre arms and a single coax wire connected to a remote antenna switch. This aerial work on 8 bands and has a 60-degree beam width. Despite achieving critical technical requirements, the antenna's three-dimensional structure presents obstacles, such as installation issues on fixed towers and risk of frost damage. The spider framework is built of stainless steel, with a compact 18-inch boom and strong angle iron arms. Tait use a variety of methods to fasten element wires and suggests placing them on the outside of the spreaders for improved insulation. The use of nylon twine or parachute cord between key attachment points allows for adjustable separation between pieces.

The ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF), functions effectively on multiple HF bands without requiring an Antenna Tuning Unit (ATU) for 40, 20, 17, 12, 10, and 6 meters. This antenna, approximately **27.51 meters** (90 feet) long with a 12.2-meter (40-foot) open-wire feeder, is a direct descendant of the _G5RV_ but offers superior multi-band resonance. It can be deployed as a horizontal dipole or an inverted-vee, with the latter requiring only a single support and maintaining an apex angle of at least 90 degrees to prevent signal cancellation. Performance data, recorded with an MFJ Antenna Analyser, indicates SWR values of 1:1 on 7.00 MHz (40m) and 14.06 MHz (20m), with SWR below 1.3:1 on 17m, 10m, and 6m. While primarily designed for these bands, the antenna can be adapted for 80m, 30m, and 15m with an ATU, preferably at the balanced feeder's base. The use of 450-ohm twin-lead for the feeder is recommended over 300-ohm for improved strength and reduced losses, especially in adverse weather conditions. This design, originally published in _RadCom_ in 1993 and featured in Pat Hawker’s "Antenna Topics," provides a compact and efficient solution for HF operation, particularly for those with limited space or resources.

This wire-beam has one radiator-element, feeded with 450-Ohm-Wireman-twinlead and needs an antenna-tuner. For the bands 6m, 10m, 12m, 15m, 17m and 20m bended reflector-elements are used. The support is a cross of 4 fibreglass-fishing-rods

The varieties of twinlead J-Poles and some performance standards, L. B. Cebik, W4RNL

40 meters elevated vertical antenna array at VA7ST

Largest general-purpose ham radio club in Twin Cities. Three repeaters, fully equipped two position HF club station, contesting, field day, and more.

A multiband wire antenna with a twinlead feedline that can be easily tuned in several bands, witha 33 ft per leg you can have a 40 to 10 meters band coverage

J-pole antenna made easy using a twinlead by W4ZT

Presents a construction project for a linear-loaded 40-meter rotatable dipole, detailing the design evolution from mid-element coils to 300-ohm twinlead loading. It covers material selection, including repurposed fishing poles and EMT conduit, and outlines the assembly process for the antenna elements and mounting plate. The resource provides specific measurements for element lengths and linear loading sections, along with SWR plots demonstrating the antenna's resonance at 7.035 MHz with a 1.1:1 SWR, and bandwidth up to 7.120 MHz below 2:1 SWR. The article documents the antenna's performance during various RTTY and CW contests, including the SARTG RTTY and SCC RTTY contests in August 2006, and the ARRL DX CW and CQWW WPX RTTY contests in February 2007. It reports successful operation at 500-1000W, noting improved performance after replacing a faulty coax cable. Specific DX contacts from British Columbia, including stations in Europe and South Africa, are listed, illustrating the antenna's capability despite its shortened length and relatively low height of 55 feet. The content highlights practical considerations such as weatherproofing the connections and supporting the fiberglass elements to prevent sagging. It also includes a brief comparison to an inverted-V at similar height and a ground-mounted vertical, noting the rotatable dipole's quieter reception. The author shares insights into the iterative design process and tuning adjustments made to achieve optimal resonance.

Over 1,000 stations in approximately 60 countries were worked using this modified twin-lead folded dipole, demonstrating its effectiveness with just 4 watts on 20 meters. This design, adapted from an ARRL Handbook concept, eliminates the shorting strap found in traditional folded dipoles, simplifying construction while maintaining performance. It utilizes readily available 300-ohm TV antenna feeder ribbon, making it a cost-effective solution for radio amateurs. The antenna's robust construction allows it to handle up to 100 watts without issues, even without a **balun**. The inclusion of a variable trimmer capacitor at the stub provides flexibility for tuning across different frequencies within a band, a practical feature for operators using transceivers like the Icom 735. Formulas are provided to calculate the precise dimensions for any desired operating frequency, enabling customization for various **HF bands**.

Why twinlead isn't necessarily a low loss feed line.

The G5RV multiband HF antenna, designed by Louis Varney (G5RV) in 1946, is a popular compromise antenna offering good overall performance on most HF bands when paired with an external antenna tuner. The basic full-size G5RV measures 102 feet across the top for 80 through 10 meter operation and is fed at the center via a 34-foot low-loss feed-stub. This interaction between the radiating section and the feed-stub facilitates matching across 80-10 meters with a standard tuner, often eliminating the need for ladder line directly to the shack. The antenna's design center frequency is 14.150 MHz, configured as a 3/2-wave dipole on 20 meters, with its 102-foot length derived from long-wire antenna formulas. Construction details emphasize the matching section, which can be open wire, ladder line (window-type), or TV twin lead. Each type has a specific velocity factor (VF) affecting its physical length for an electrical half-wave on 14 MHz; for instance, open wire requires 33.7 feet (VF 0.97), ladder line 31.3 feet (VF 0.90), and TV twin lead 28.5 feet (VF 0.82). The article provides formulas for calculating these lengths and discusses the antenna's behavior on individual bands, from 3.5 MHz where it acts as a shortened dipole, to 28 MHz where it functions as two three-half-wave long-wire antennas fed in-phase. Practical construction notes include recommendations for vertical descent of the matching section, sealing the coax junction, providing strain relief, and winding a coaxial choke coil to mitigate common mode current. The resource also presents dimensions for double-size (204 ft) and half-size (51 ft) G5RV versions, along with their corresponding matching section lengths for various line types, making it a versatile reference for hams considering this classic wire antenna.

This document contains the detailed instructions to build a homemade lindenblad antenna using a twin-lead as dipole elements. This document contains 9 pages and includes a detailed construction sequence and some drawings to build this antenna for UHF and VHF ham radio bands

A folded dipole using twin lead By W8HDU

Open-Wire/Twinlead Antenna Switch

An easy portable VHF antenna to build for ARES - RACES work is the 300 Ohm Twin Lead JPole antenna

Minnesota's DX Connection

Home made twin paddle morse code key designed by Steve Taylor G4EDG.

Manufactures and sells coaxial connectors, coaxial adapters, coaxial cables, attenuators, directional couplers, fiber optic connectors, fiber optic adapters, fiber optic cables, coaxial switches, terminators, twinax connectors and cables and tools.

2 Meter Slim Jim Antenna Using 300 Ohm Twinlead

The Twin Cities Repeater Club (TCRC) is a charitable public service organization, incorporated as a non-profit Minnesota corporation, that owns four VHF and UHF repeaters in the Minneapolis/Saint Paul metropolitan area.

A Batwing Antenna Design Challenge

The twin-lead portable rollup J-Pole antenna, assembled and ready for deployment

TwinsLAN is Minnesota's only amateur radio club devoted to digital communications

An home made doblet antenna made with two Slinkys that are aproximately five meters in length connected with a twin-feed connected to a balanced ATU

English operating manual of the Yaesu FT-2800M transceiver

Operating Morse code (CW) relies on a diverse array of **telegraph keys**, each with unique characteristics and historical significance. This resource presents a personal collection of such keys, offering visual documentation and details on various models. It features early Marconi keys from the 1900s, including specific models like the Marconi Air Ministry Key and Marconi Coastal Station Keys, alongside **Vibroplex** bugs and JRC keys. The collection also highlights rare items such as the Brown Brothers Magnetic Twin Paddle Key, the Eddystone Bug Key, and Swedish SRA Ericsson Keys. Enthusiasts can view examples of GPO Double Current & Single Current Keys, Navy NATO Keys, and specialized aircraft and maritime keys. The site includes information on historical training devices like the OMNIGRAPH and a Morse Inker from 1900, providing context for the evolution of telegraphy equipment. Additionally, the resource showcases unique items like the B2 Spy Set SOE Agents Key and a WW2 Junker U-BOAT KEY, illustrating the varied applications of Morse keys throughout history. The author, G0RDO, also shares details on a home-made paddle key and invites inquiries for acquiring interesting Morse keys.

The original SurplusEQ.com domain, once a hub for amateur radio operators and electronics enthusiasts seeking test equipment, meters, and various high-tech components, has been repurposed. Historically, such platforms facilitated the acquisition of essential gear for shack setups, antenna analysis, and general electronics work, often providing cost-effective alternatives to new retail purchases. The site's previous focus on "test equipment, meters, testers" directly supported the technical aspects of the hobby, from RF measurements to circuit diagnostics. Currently, the domain points to a gambling platform named "SEMUTWIN," offering online slot games, live casino options, and other digital wagering activities. This shift represents a complete departure from its former identity as a resource for surplus electronics and amateur radio-related equipment. The content now features game titles like "Sweet Bonanza Super Scatter" and "Gates of Olympus Super Scatter," alongside promotional offers for online gaming.

Definition and samples of Twin Lead Cables at wikipedia

Sort of similar to the one of the 6m omni. Instead of using twin-lead, this design makes use of a more or less regular double bazooka antenna (coaxial dipole). Your attention shall be drawn to the available standart literature, such as Rothammel. In order to "compute" the dimension, Karl Rothammel mentioned that the total length of the dipole shall be 95% of the free-space wavelength. The short-circuit bridges (closing the folded dipole) are to be placed at a distance-fraction being equal to the velocity factor of the coax cable used, which will be 66% using RG-58 or RG174.

Experimenting a low impedance feedline by G3TXQ

Calculate the inductance of twin lead online

A simple 3D Paddel CW Key made of plastic with a standard 3d printer

Demonstrates the ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF) that improves upon the G5RV by offering direct resonance on multiple bands without an antenna tuner. The resource details the antenna's 90-foot length and 40-foot 450-ohm twin lead downlead, emphasizing its suitability for hams with limited space or budget. It covers both horizontal and inverted-V configurations, noting the inverted-V's single-support advantage and the importance of maintaining an apex angle of at least 90 degrees to prevent signal cancellation. The author, G3UKV, shares his preference for 450-ohm twin lead over 300-ohm due to its superior strength and lower losses, especially in wet conditions, drawing from his extensive field experience. The document presents recorded SWR and impedance (R) measurements taken with an MFJ Antenna Analyzer, confirming excellent performance on 40m, 20m, 17m, 12m, 10m, and 6m, often with SWRs below 1.3:1. It also discusses the antenna's tunability on 80m with an ATU and suggests a method for 160m operation. G3UKV recounts receiving "excellent reports" on 7 MHz and 14 MHz, validating the antenna's effectiveness. Practical advice includes keeping antenna ends clear of ground by at least a yard to avoid detuning and the recommendation of a 1:1 current balun where the 450-ohm feeder connects to 50-ohm coax.

The Slim Jim VHF antenna, originally designed by G2BCX, is a folded half-wave dipole fed by a quarter-wave matching section. This version, built from a recycled professional aluminum dipole, demonstrates that various materials—such as copper, brass, or twin-lead—can be used. The article details the antenna’s construction, required materials, and tuning process, emphasizing mechanical stability and ease of assembly. With proper adjustment of the feed point, it provides excellent SWR across the band. Its durability and simplicity make it a practical and efficient VHF antenna solution.

The PA0FRI Unbalanced/Balanced ATU is a home-built antenna tuner designed to efficiently match a W8JK 2-element beam antenna fed with a 450-ohm twin lead. Based on PA0FRI’s S-Match design, it optimizes energy transfer while maintaining balance, reducing losses, and ensuring proper radiation. The tuner uses a roller inductor, air variable capacitors, and a T200 iron powder coil, allowing fine-tuning across 14-50 MHz. Extensive lab tests confirm minimal attenuation and precise impedance matching, making it a reliable and efficient ATU for balanced antennas.

Addresses the common challenge of constructing effective dual-band antennas for VHF/UHF operations, specifically detailing a J-pole design. It covers the theoretical underpinnings, including calculations for quarter-wavelength radiator and stub sections, accounting for velocity factor and design frequency. The resource provides practical construction guidance using readily available materials like TV twin lead and coaxial cable, culminating in an antenna with a total length of approximately 52 inches. Performance metrics are presented, showing a measured SWR of 1.7:1 or better across most of the 2-meter band and less than 2:1 across the 70-cm band. These SWR measurements, referenced to 50-ohm impedance, were taken at the transmitter end of the feed line. The article also touches upon the necessity of a balun for proper impedance matching between the balanced J-pole and unbalanced coaxial feed line, suggesting a split-core cylindrical ferrite for this purpose.

This article by Fred Delaney, K1DU, details the construction of a J-Pole antenna using 450 Ohm ladder line, designed for operation on the 2-meter (144 MHz) and 70-centimeter (440 MHz) bands. The design is based on an earlier concept using 300 Ohm TV twinlead by KD6GLF. The J-Pole is presented as a suitable indoor, freestanding antenna, particularly useful in areas prone to lightning or for hams with antenna restrictions. It can also be configured for portable use, such as a backpack version for camping. The antenna is vertically polarized and consists of a ¾ wavelength radiator and a ¼ wavelength matching stub, operating as an end-fed half-wave antenna. It does not require ground radials and offers a gain of 2.4dB over isotropic. The article provides the formulas and calculations for the ¾ wave radiator and ¼ wave stub, using a velocity factor of 91% for 450 Ohm ladder line. Specific dimensions for 146 MHz are given: a ¾ wave radiator of 55 3/16 inches and a ¼ wave stub of 18 3/8 inches. Construction involves cutting a 57¾-inch piece of ladder line and stripping 4 inches from one end.